John, with his brother George, operated a printing establishment in New York City for several years. A description of the business appears in the History and Commerce of New York:10
GAZLAY BROTHERS, Printers, Nos. 157 and 159 William Street.--This business was established fifteen years ago at No. 106 Fulton Street, but the trade of the house increased so rapidly that these premises soon proved totally inadequate, and they removed to their present eligible location. Here they occupy spacious and commodious premises, 45 x 100 feet, the equipment of which cannot be surpassed for convenience and completeness by that of any similar establishment in the city. It comprises three large cylinder presses, and seven job presses of the most improved description, besides hundreds of fonts of the newest and handsomest faces of book and type, and everything required in conducting a first class printing establishment. Constant employment is given to thirty three skilled workmen, and every description of book, job, and mercantile printing is done, from the smallest card up to a newspaper. The individual members of the firm, Messrs. John C. and George E. Gazlay, are thoroughly practical printers of many years’ experience, and have always been noted for the artistic taste they display in all work entrusted to them.